In multi-unit dwellings, it is known for each unit to include a coil and a fan. In the winter, warm fluid is produced in a central boiler and delivered to the coil, such that air can be forced past the coil and heated. In the summer, cold fluid is produced in a central chiller and delivered to the coil, such that air can be forced past the coil and cooled. It is commonplace for the coil and fan to be mounted in a cabinet.